Hi MattYour quite right. It was that. I was using the syntax for personal geodatabases when I'm working with an SDE geodatabase. My revised code is:
arcpy.SelectLayerByAttribute_management ("Full area polygons layer outline only v5", "NEW_SELECTION", """ [AREA_NAME] = 'AREA 3' """)
Saying that after I got my new code to work and it had selected the features, ArcMap shortly froze. However on restarting ArcMap it then worked, after several error messages about valid index range being passed. That may be a freak event, as I'm new to working with the Python window.Kind regards